nthomso3 Wrote:I have had a private message detailing a mistake I've made but also will explain my thoughts a little clearer. If only everyone was willing to post publicly - we'd probably get a whole lot more answers.
Indeed a discussion group does require people to be willing to discuss! Interesting to have such a flurry of activity today; a few people on study leave just prior to exam I wonder?
nthomso3 Wrote:I made the mistake of including MAY-FA in the last post as I thought the linespeed is 120km/h but it's actually 140km/h so would probably just be MAR.
I believe points at 1320 are 40km/h (25mph) as I have found nothing suggesting otherwise. Hence the aspect reading over them reverse would need to be approach released if straight route speed higher by more than 10mph. However the UVB only reads over a similar speed turnout at 1750 or another one at 1900 to the fixed red at the right hand end of the UM platform [hands up- who forgot it?]
I'd therefore be tempted to define the speed in the Down direction of the UVB to be 35mph and thus get rid of the need to approach release the route from the viaduct to the DVB; after all that is the route that all the through traffic takes so approach releasing it delays traffic and indeed could give a SPAD risk due to drivers conditioned to it's last mninute clearance. Assuming the signal for that juction is actually on the far side of the viaduct any SPAD would be of high consequence, and frankly the sigmal so much prior to the junction that approach release really pretty ineffectual at controlling risk of driver overspeeding. [I haven't done this layout at all- I am just staring at a blank layout- but I am still wondering whether a signal leaving the viaduct at around 1220 would be a good idea as hinted at earlier]
nthomso3 Wrote:The other comment was in respect to the standage. My thoughts to achieve maximum standage was to have only a IPL on the exit of the branch rather than a main signal to eliminate the overlap. This leaves two options to getting a freight train into the down valley branch - 1. have a shunt route over the viaduct up to the IPL, or,
2 - a main route up to the station then a repelling move back.
If you mean what I think you mean then you are off-beam here. A running move MUST end at a main signal having a red aspect except in the limited case of a bufferstop light or a reflectorised stop board (typically in reception lines, entrances to depots etc). Not sure why you think that an independent PL would increase standage (the O/L need not be contained within the loop- it can extend outside it at the cost of being a bit restrictive whilst a train is running in but then release once train timed to a stand). Of course nowadays on NR we often provide O/L beyond GPL signals anyway!
Aah, now I see where Astubbs comment re PL move over diagram came from. No, I agree with him; you wouldn't do that. Can't say I totally follow your wording about getting freight (from where?) to the DVB (which bit?). I think you are on the wrong lines here anyway...
PJW